Published on: March 16, 2015
by Heidi Mitchell for The Wall Street Journal:
Stress can be memory’s best friend. But when you forget where you put the car keys, stress can also make you feel stupid. One expert, Rajita Sinha, a professor of psychiatry and neurobiology at Yale University, sorts through the effects of stress on memory, and its troubling relationship to dementia.
People use the term “stress” loosely. Dr. Sinha defines it as the process by which we react to stimuli that are threatening, challenging or overwhelming. “It is a complex system of cortisol, adrenaline, peptides and other hormones and chemicals that help us respond, adapt and bring our bodies back to a stress-free baseline,” says Dr. Sinha, who is director of the Yale Stress Center.
Stress works on a spectrum, the psychiatrist says. At one end is controllable stress, where if you take the correct action you can regain control. “Imagine you notice the fridge is almost empty, but if you hurry you can get to the store before a forecast snowstorm hits,” she says. At the other end is uncontrollable stress. Losing your home or ending a significant relationship would fit in this category, she says. The two types often overlap.
Leaving its Mark
The brain grasps an uncontrollable threat very quickly and can retrieve relevant information immediately when presented with the same acute stress again, Dr. Sinha says. When you are out alone on a street at night, your stress response might help keep you alert the next time you are alone and feel in danger. “That experience sharpens the mind and encodes an impression,” she says.
Controllable stresses, too, leave an imprint, such as not having enough time to study for an exam. “Your mind will remember that experience, and you will allow for more time to study before the next test,” Dr. Sinha says.
The Memory Link
Yet studies looking at multiple simultaneous stresses—either controllable or uncontrollable—show they lead to poor memory retrieval “because the brain’s capacity to think is fractured,” says Dr. Sinha.
Generally someone who is stressed will be able to focus on the task at hand but might forget things that aren’t specifically related. A person running late for a meeting may forget where he put his keys, or a homeowner threatened with foreclosure might not recall his own phone number. “What makes us human is to think creatively and emotionally, to allow us to be rational and wise,” Dr. Sinha says. “But if you have multiple things going on, that is thrown out the window, and you are emotionally overwhelmed.”
Recent studies have shown the risk for dementia and other memory-related illnesses rises significantly the more people encounter uncontrollable stress. Dr. Sinha says studies using brain scans show that loss of a significant other or witnessing violence does take a toll. “Research has shown that whole branches of brain cells can shrink and start to disappear,” she says. “That doesn’t mean that if you get divorced, you’ll get dementia. But the risks are there.”
The good news is the brain is dynamic, and neuron damage can be reversed. Dr. Sinha says brain research has documented so-called neurogenesis, although science hasn’t pinpointed what sorts of stress-related memory loss can be reversed, she says.
Dr. Sinha advises patients to set everyday stress-management goals: Get enough sleep, stay hydrated, eat small and healthy meals regularly to avoid glucose drops, and exercise to maintain high energy. Be aware of stress signs. “If you continue to notice forgetfulness when faced with common stresses, talk to your doctor,” Dr. Sinha says.
Avoid multitasking whenever possible, she adds. “If you do 10 different things at once, you’re only using one-tenth of your brain for each task, which makes it hard to perform at your peak level,” Dr. Sinha says. “That can increase stress levels.” The result: Forgetting where those darn keys are.
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